Neural Circuit Recording from an Intact Cockroach Nervous System

The cockroach ventral nerve cord preparation is a tractable system for neuroethology experiments, neural network modeling, and testing the physiological effects of insecticides. This article describes the scope of cockroach sensory modalities that can be used to assay how an insect nervous system responds to environmental perturbations. Emphasis here is on the escape behavior mediated by cerci to giant fiber transmission in Periplaneta americana. This in situ preparation requires only moderate dissecting skill and electrophysiological expertise to generate reproducible recordings of neuronal activity. Peptides or other chemical reagents can then be applied directly to the nervous system in solution with the physiological saline. Insecticides could also be administered prior to dissection and the escape circuit can serve as a proxy for the excitable state of the central nervous system. In this context the assays described herein would also be useful to researchers interested in limb regeneration and the evolution of nervous system development for which P. americana is an established model organism.     

Testing adaptive significance of host manipulation with a parasitoid wasp

According to the extended phenotype hypothesis, certain parasites manipulate the host's behaviour which ultimately enhances the transmission of parasite genes into the next generation. The parasitoid wasp Ampulex compressa attacks and stings its cockroach Periplaneta americana host and lays an egg on the cockroach's leg. Before the wasp's oviposition, the stung cockroach engages in excessive self-grooming for about 30 min. The prey location hypothesis posits that self-grooming may allow the wasp to easily locate its host before transporting it to the nest. To test this hypothesis, we manipulated the mobility of the stung cockroach under different spatial constraints. Latencies to locate stung cockroaches with unlimited movement were similar than latencies to locate stung, but motionless cockroaches irrespectively of spatial constraints. Wasps were less willing to lay eggs and seal an entrance to the burrow in treatments with motionless cockroaches which suggests that if the expected reproductive success is low, then parental investment decreases. Our results provide no support for the location hypothesis and call for further experimental investigation of the extended phenotype hypothesis in parasite–host interactions.     

Cyclic gas exchange in the giant burrowing cockroach, Macropanesthia rhinoceros: effect of oxygen tension and temperature

The giant burrowing cockroach, Macropanesthia rhinoceros, is endemic to north-eastern Australia and excavates a permanent burrow up to 1m deep into soil. Using flow-through respirometry, we investigated gas exchange and water loss at three different oxygen tensions (21%, 10% and 2% at 20 degrees C) and temperatures (10, 20 and 30 degrees C at 21% oxygen). M. rhinoceros employ cyclic gas exchange (CGE) making the species by far the largest insect known to engage in discontinuous ventilation. CGE featured rhythmic bursts of CO(2) dispersed among inter-burst periods of reduced output. CGE was most commonly observed at 20 degrees C and degraded at <10% oxygen. Mild hypoxia (10% oxygen) resulted in a lengthening of the burst period by approximately two-fold; this result is complementary to oxygen consumption data that suggests that the burst period is important in oxygen uptake. When exposed to severe hypoxia (2% oxygen), CGE was degraded to a more erratic continuous pattern. Also, during severe hypoxia, total water loss increased significantly, although CO(2) release was maintained at the same level as in 21% oxygen. During CGE, an increase in temperature from 10 to 20 degrees C caused both water loss and CO(2) output to double; from 20 to 30 degrees C, CO(2) output again doubled but water loss increased by only 31%.     

A cockroach that jumps

We report on a newly discovered cockroach (Saltoblattella montistabularis) from South Africa, which jumps and therefore differs from all other extant cockroaches that have a scuttling locomotion. In its natural shrubland habitat, jumping and hopping accounted for 71 per cent of locomotory activity. Jumps are powered by rapid and synchronous extension of the hind legs that are twice the length of the other legs and make up 10 per cent of the body weight. In high-speed images of the best jumps the body was accelerated in 10 ms to a take-off velocity of 2.1 m s(-1) so that the cockroach experienced the equivalent of 23 times gravity while leaping a forward distance of 48 times its body length. Such jumps required 38 μJ of energy, a power output of 3.4 mW and exerted a ground reaction force through both hind legs of 4 mN. The large hind legs have grooved femora into which the tibiae engage fully in advance of a jump, and have resilin, an elastic protein, at the femoro-tibial joint. The extensor tibiae muscles contracted for 224 ms before the hind legs moved, indicating that energy must be stored and then released suddenly in a catapult action to propel a jump. Overall, the jumping mechanisms and anatomical features show remarkable convergence with those of grasshoppers with whom they share their habitat and which they rival in jumping performance.     

美洲大蠊变应原Cr PI的表达、纯化与免疫学特性鉴定

以阳性噬菌体克隆为模板,通过PCR扩增出目的基因片段并克隆入T载体,经测序证实为美洲大 蠊Periplaneta americana变应原Cr PI后,将该基因亚克隆入表达载体pGEX-5X-1。美洲 大蠊变应原Cr PI在大肠杆菌中得到高效表达,但主要以包涵体形式存在于沉淀中。目的蛋白溶 于6 mol/L盐酸胍并经稀释复性后,经Glutathione Sepharose^TM4B亲和层析,纯度达 90%以上。以蟑螂过敏病人血清进行免疫印迹检测,结果显示重组变应原具有良好的IgE结合活 性。     

German Missionaries and Australian Anthropology

ABSTRACT

In their primary task of converting Indigenous Australians to Christianity, German missions active in various parts of Australia through the nineteenth and into the twentieth century recorded relatively few successes. On the other hand, their endeavours in observing and recording Aboriginal languages and cultures have left a rich – and yet frequently overlooked – anthropological legacy. A common element in that legacy is their work in the area of linguistics, which they understood to be a necessary foundation for their evangelical work. Nonetheless, caution must be exercised in evaluating the German missionary contribution to Australian anthropology according to either national or religious paradigms. German anthropology, as practised within the community of missionaries and outside, evinces a variety of theoretical and methodological approaches. Moreover German anthropologists, including missionaries, were by the late nineteenth century connected into international knowledge networks.     

Erhard Eylmann’s Missionary Position

ABSTRACT

The German anthropologist Erhard Eylmann relied heavily on assistance provided by missionaries when he undertook fieldwork in Australia. During two periods at the Hermannsburg mission he developed a strained relationship with Carl Strehlow. In his major work Eylmann wrote a damning critique of missionaries. While there was a level of personal animosity between Eylmann and Strehlow, at the heart of the antagonism were fundamental differences concerning the nature and function of the discipline of anthropology. The missionaries sought anthropological knowledge to promote mutual understanding, above all through language, as a prelude to conversion to Christianity. They proceeded from the assumption that the future of Indigenous Australians would be within the context of the adoption of Christian belief systems. Eylmann in contrast took the view that the differences between Europeans and Indigenous Australians were physical, essential and insuperable. Sceptical about the possibility of achieving mutual understanding, he devoted his fieldwork primarily to describing, recording and collecting for the purpose of assembling a detailed record of a population he believed destined for extinction. Eylmann and German missionary anthropologists such as Strehlow had in common that they stood outside the paradigm of British social evolutionistic thinking which dominated Australian anthropology around the turn of the century at the time. At the same time, the differences in the anthropological endeavours of Eylmann and Strehlow indicate the great breadth of approaches opening up within German anthropology. In particular they point to the emergence of an ‘antihumanist’ turn at the end of the nineteenth century.     

Phospholipid composition and pheromonal activity of nuptial secretion of the male German cockroach, Blattella germanica

As a part of the sequential courtship behavior of the German cockroach, Blattella germanica, females feed on the nuptial secretion from the male tergal glands. The pheromonal secretion, consisting mainly of oligosaccharides and phospholipids, strongly elicits a feeding response in virgin females. The phospholipids were composed of phosphatidylethanolamine and phosphatidylcholine. Their fatty acid compositions were determined by chromatographic and enzymatic methods. Although an authentic blend of phospholipids (1,2-dioleoylphosphatidylethanolamine and 1,2-dioleoylphosphatidylcholine) showed a marginal phagostimulant activity, addition of the blend to an authentic blend of oligosaccharides (maltose and maltotriose) strongly enhanced the activity to nearly the level of the crude extract. These results indicate that the nuptial feeding behavior is elicited by a synergistic action between phospholipids and oligosaccharides.     

The Romantic Conception of Robert J. Richards

In his new book, The RomanticConception of Life: Science and Philosophyin the Age of Goethe, Robert J. Richardsargues that Charles Darwin's trueevolutionary roots lie in the German Romanticbiology that flourished around thebeginning of the nineteenth century. It isargued that Richards is quite wrong in thisclaim and that Darwin's roots are in theBritish society within which he was born,educated, and lived.     

德国人文聚落区生态单元制图国家项目

联邦德国自然保护法、德国各州自然保护法要求在自然景观区和人文聚落区保护、管理和发展自然。实现这一法律要求 ,必须以现实的、全面的、高质量的、与自然保护原则相匹配的数据为基础。实践证明 ,城乡生态单元制图是获取和解释这些数据不可或缺的手段。德国人文聚落区生态单元制图始于 1 978年 ,同年组建成立了德国联邦与各州自然保护部门参加并联合协调的“人文聚落区生态单元制图工作组”。 1 986年工作组提出了德国人文聚落区生态单元制图基本方案 ,1 993年完成基本方案修订版。基本方案的目标是在全国范围建立标准制图方法 ,使获取的科学数据可以相互比较。至 2 0 0 0年 ,德国在人文聚落区生态单元制图项目上的投资约合 2亿马克 ;至 2 0 0 1年 3月 ,德国有 2 2 3个大中城市已经完成或正在实施生态单元制图 ,人文聚落区生态单元制图已经成为德国各级政府生态规划的基本工作内容。